A Novel 180–210 GHz Single Sideband Mixer Using Filtering Waveguide-Microstrip Transition Structure

In this letter, we proposed a novel 180–210 GHz single sideband (SSB) Schottky diode-based subharmonic mixer (SHM), which features in simpler structure and fabrication compared with existing methods. Image rejection of the 220–250 GHz upper sideband (USB), as well as impedance matching, was achieved by a filtering waveguide-microstrip transition structure at the radio frequency (RF) input, rather than using traditional waveguide filters. Eventually, the mixer was measured to show great performance, including a SSB conversion loss (CL) of 8–12 dB across the passband, and an image rejection ratio (IRR) of 15–35 dB.